This invention relates to an apparatus and method for suspending and positioning objects by the use of acoustical energy. In many instances, the study of materials and material processes and the determination of their properties can be more readily accomplished when the specimens under study are maintained out of contact with the walls of containers and solid supports. A levitated specimen of a material may be advantageously heated in a levitation furnace or by a spot heating device such as a laser.
Heretofore, apparatus has been proposed for suspending objects in zero gravity such as disclosed in U.S. Pat. No. 3,882,732 wherein three dynamic speaker devices are oriented along the three major axis of a chamber and are driven so as to provide a spherical nodal position at the intersection wherein an object may be suspended.
Another prior device commonly referred to as a St. Clair device has been utilized wherein a solid cylindrical vibrating element having a planar face is driven in an ultrasonic generator and a planar reflector is positioned in such a manner above the vibrator element that a standing wave field between the vibrating element and reflector is set up whereby a small object may be suspended in mid-air supported only by the radiation pressure. However, the leviation force produced by such a device is limited having application mainly to lighter materials.